Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Treating polymer containing material or treating a solid...
Patent
1996-07-08
1999-03-09
Krass, Frederick
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Treating polymer containing material or treating a solid...
528502R, 528503, C08G 6388, C08G 390
Patent
active
058802541
ABSTRACT:
A method for producing a polylactic acid includes the steps of (a) crystallizing polylactic acid pellets obtainable by direct polymerization of lactic acid or ring-opening polymerization of lactide; and (b) removing low-molecular components having a weight-average molecular weight of 1,000 or less in the resulting crystallized, solid polylactic acid pellets by gasifying the low-molecular components to obtain polylactic acids with substantially no low-molecular components. In this method, an apparatus for removing low-molecular components in polylactic acid pellets includes a crystallizing means for maintaining a temperature between equal to or higher than a glass transition temperature of polylactic acid pellets and equal to or lower than the melting point thereof, while fluidizing the polylactic acid pellets; and a reactor for allowing a heated inert gas and/or heated air to pass through the resulting crystallized, solid polylactic acid pellets obtained by the crystallizing means.
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Fujii Yasuhiro
Ito Masahiro
Ohara Hitomi
Oota Masaaki
Sawa Seiji
Krass Frederick
Shimadzu Corporation
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